1. Field of the Invention
The present invention relates to processes and apparatus for cooling high viscosity sauces containing ingredients in the form of solid pieces.
2. Description of the Related Art
It is generally known to cool low-viscosity food products using vacuum vapor evaporation. However, this process can generally only be used to a limited extent for high-viscosity food product, since on the one hand, the thin evaporation layer necessary for the vacuum cooling often cannot be achieved and on the other hand, the ingredients in piece form can be damaged by mechanical processes and, as a result, the overall quality is reduced.
It has typically been the practice until now for high-viscosity sauces containing ingredients in the form of solid pieces, such as vegetable, fruit or meat for example, to be manually discharged by filling the sauces into plastic containers, with a capacity of about 10 kg, at a temperature of about 80.degree. C. These plastic containers are then cooled in a cooling chamber at a temperature of +3.degree. C. for about 48 hours. In this operation, filling, cooling, discharging and cleaning the containers represent considerable work.
Continuously operating systems such as scraped surface coolers (liquid-cooled tubes with mechanical internal scraping devices) have generally not proven to be successful for sauces containing ingredients in the form of solid pieces, since the strong mechanical scraping action has the effect that, depending on the ingredients in piece form used, the end product becomes a uniform paste, which does not meet customer requirements in many instances.
Cooling by using tube cooling systems is also generally not possible, since the desired low temperature of +3.degree. C. and the necessary high viscosity of the sauces of up to 22 Pas can cause the multitube cooler to freeze up. What is more, the ingredients in piece form are also damaged by the high pump pressures necessary in the cooling of high-viscosity sauces in tube systems.